An interesting observation from Fig. REF  is that the mean losses predicted with a finite outer scale and a non-zero inner scale are lower than the mean losses predicted with an infinite outer scale and a zero inner scale. Such an observation can be explained mainly by the fact that the presence of a finite outer scale reduces the amount of beam wandering and long-term beam spreading [1]}. This observation does not refute the conventional wisdom that the channel loss in the uplink channel is higher than the channel loss in the downlink channel. However, this observation does indicate that the disadvantage of an uplink channel may be overestimated in some models.
We believe that setting a finite outer scale and a non-zero inner scale (according to the empirical Coulman-Vernin profile) is more relevant (rather than simply setting \(L_0=\infty \)  and \(l_0=0\) ) when studying the atmospheric propagation of light through a satellite-based channel. Therefore, in the rest of this work, we will utilize the results from the phase screen simulations that adopted a finite outer scale and a non-zero inner scale.
